Chemical sensor and method of detecting chemical

Abstract

A chemical substance sensor is formed by arranging a sensor chip on a microcartridge formed with a micropassage and further arranging a prism on this sensor chip. In the sensor chip, a metal thin film is formed on one surface of a substrate, and an immobilizer is further formed thereon. In order to detect a chemical substance with the chemical substance sensor, a solution containing a sample and odorant binding protein is fed to the micropassage for immobilizing the odorant binding protein to the immobilizer. The chemical substance contained in the sample is detected on the basis of the quantity of immobilization of the odorant binding protein.

1 . A chemical substance sensor comprising: 
 a cartridge having a passage capable of feeding a solution containing a sample and odorant binding protein;    an immobilizer capable of coming into contact with said solution in said passage and arranged along a flow of said solution for immobilizing said odorant binding protein contained in said solution; and    a detector that detects the quantity of immobilization of said odorant binding protein contained in said solution to said immobilizer on the basis of physical change of an interface between the solution containing said sample and said odorant binding protein and said immobilizer.    
     
     
         2 . The chemical substance sensor according to  claim 1 , wherein said physical change is change of a refractive index.  
     
     
         3 . The chemical substance sensor according to  claim 2 , wherein said detector includes: 
 a condenser arranged on said immobilizer,    an irradiator that irradiates said interface with light through said condenser,    a refractive index measuring device that measures the refractive index on the basis of reflected light from said interface through said condenser,    an immobilization quantity calculator that calculates the quantity of immobilization of said odorant binding protein to said immobilizer on the basis of the change of said refractive index measured by said refractive index measuring device, and    a determiner that determines presence/absence of a chemical substance in said sample on the basis of the quantity of immobilization calculated by said immobilization quantity calculator.    
     
     
         4 . The chemical substance sensor according to  claim 3 , wherein said refractive index measuring device includes: 
 a light-transmitting substrate having said condenser arranged on one surface,    a metal thin film arranged between the other surface of said substrate and said immobilizer,    a photoreceptor that receives the reflected light from said interface, and    a resonant angle measuring device that measures a resonant angle in surface plasmon resonance on the basis of an output from said photoreceptor thereby measuring change of the refractive index by the reflected light from said interface.    
     
     
         5 . The chemical substance sensor according to  claim 3 , wherein said irradiator irradiates said interface with monochromatic light through said condenser.  
     
     
         6 . The chemical substance sensor according to  claim 5 , wherein said irradiator irradiates said interface with a parallel component of said monochromatic light through said condenser.  
     
     
         7 . The chemical substance sensor according to  claim 1 , wherein said condenser is a prism.  
     
     
         8 . The chemical substance sensor according to  claim 1 , wherein said cartridge is a microcartridge having a micropassage.  
     
     
         9 . The chemical substance sensor according to  claim 1 , wherein said odorant binding protein has a dimer structure.  
     
     
         10 . The chemical substance sensor according to  claim 1 , wherein said odorant binding protein is bovine derivation odorant binding protein.  
     
     
         11 . A method of detecting a chemical substance comprising steps of: 
 arranging an immobilizer for immobilizing odorant binding protein contained in a solution on a cartridge having a passage capable of feeding said solution containing a sample and said odorant binding protein so as to come into contact with said solution in said passage along a flow of said solution;    feeding the solution containing the sample and said odorant binding protein into said passage;    detecting the quantity of immobilization of said odorant binding protein to said immobilizer on the basis of physical change of an interface between the solution containing said sample and said odorant binding protein and said immobilizer; and    analyzing a chemical substance contained in said sample on the basis of said detected quantity of immobilization of said odorant binding protein.    
     
     
         12 . The method of detecting a chemical substance according to  claim 11 , wherein said analyzing step includes a step of comparing the quantity of immobilization of said odorant binding protein in a sample containing no chemical substance with said detected quantity of immobilization of the odorant binding protein to determine presence/absence of said chemical substance on the basis of the result of the comparison.  
     
     
         13 . The method of detecting a chemical substance according to  claim 11 , wherein said physical change is change of a refractive index.  
     
     
         14 . The method of detecting a chemical substance according to  claim 11 , wherein said step of analyzing includes a step of analyzing affinity between the chemical substance contained in said sample and said odorant binding protein on the basis of said detected quantity of immobilization of the odorant binding protein and discriminating the chemical substance contained in said sample on the basis of said affinity.  
     
     
         15 . The method of detecting a chemical substance according to  claim 11 , wherein said step of analyzing includes a step of determining the chemical substance contained in said sample on the basis of said detected quantity of immobilization of the odorant binding protein.  
     
     
         16 . The method of detecting a chemical substance according to  claim 11 , wherein said odorant binding protein has a dimer structure.  
     
     
         17 . The method of detecting a chemical substance according to  claim 11 , wherein said odorant binding protein is bovine derivation odorant binding protein.  
     
     
         18 . The method of detecting a chemical substance according to  claim 11 , wherein said step of detecting includes steps of: 
 irradiating said interface with light through a condenser,    measuring a refractive index by reflected light from said interface through said condenser,    calculating the quantity of immobilization of said odorant binding protein to said immobilizer on the basis of change of said measured said refractive index, and    determining presence/absence of the chemical substance in said sample on the basis of said calculated quantity of immobilization.